PROJECT SUMMARY/ABSTRACT Candidate: I am a behavioral health researcher with expertise in the social determinants of HIV, with a particular emphasis on prevention of mother-to-child transmission (PMTCT) in sub-Saharan Africa. My long-term career goal is to be a tenure-track professor in a school of public health with a robust research portfolio focused on family-based HIV prevention and treatment strategies. My prior training and experiences have enabled me to conduct rigorous research on the social and behavioral aspects of HIV in various global settings. However, to become a top investigator in my field capable of securing R01 funding, I require additional training and mentorship in intervention design and evaluation. The K99/R00 Pathway to Independence Award is a logical progression from my previous research and training. Under the mentorship of an exceptional team of researchers, I will focus my training phase of the award on career development activities that facilitate my transition to an independent behavioral HIV investigator capable of leading intervention trials in resource limited settings. Mentored Phase Research (K99, years 1-2): The effectiveness of PMTCT programs is dependent on optimizing pregnant and postpartum women?s adherence to antiretroviral therapy (ART) and sustained engagement in care. In high HIV prevalence settings of sub-Saharan Africa, such as Zambia, women are lost- to-follow up at alarming rates across the cascade of care. Contextual factors, such as relationship dynamics with male partners (relationship satisfaction, communication, conflict resolution), are a long-overlooked influence in women?s PMTCT-related health behaviors. Couples counseling interventions in the region have proven successful in strengthening relationships and promoting some HIV prevention behaviors, such couples HIV testing. In order to test if a couples counseling approach can extend to PMTCT outcomes in Zambia, I will refine a couples counseling intervention for HIV-positive pregnant women and their male partners (Aim 1). The intervention is based on elements of my mentors? successful couples counseling models and uses a unique adaptive design. I will refine the content and delivery of the proposed intervention through qualitative interviews and focus groups with HIV-positive pregnant women, their male partners, and service providers, while engaging stakeholders and building my research capacity in this setting. Independent Phase Research (R00, Years 3- 5): I will implement a single-site randomized controlled trial of the couples counseling intervention (n=238 couples; 119 per arm) and assess service utilization and PMTCT outcome indicators, including women?s viral load at 9 months postpartum, self-reported ART adherence, and retention in PMTCT care (Aim 2). I will also establish the effect of the intervention on intra- and inter-personal mechanisms I hypothesize to be on the causal pathway influencing PMTCT outcomes (Aim 3) through behavioral surveys at baseline, 3 and 9 months postpartum. Future Directions: Findings from this study will provide evidence of the preliminary efficacy of the couples counseling intervention to promote PMTCT adherence and retention, which will be used to develop a larger multi-site R01 trial with longer-term HIV outcomes.